Merge pull request #850 from ammaraskar/through

Report double-free in through crate

crates/through/RUSTSEC-0000-0000.md

@@ -0,0 +1,22 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "through"
+date = "2021-02-18"
+url = "https://github.com/gretchenfrage/through/issues/1"
+categories = ["memory-corruption"]
+keywords = ["memory-safety", "double-free"]
+
+[versions]
+patched = []
+```
+
+# `through` and `through_and` causes a double free if the map function panics
+
+`through` and `through_and` take a mutable reference as well as a mapping
+function to change the provided reference. They do this by calling `ptr::read`
+on the reference which duplicates ownership and then calling the mapping
+function.
+
+If the mapping function panics, both the original object and the one
+duplicated by `ptr::read` get dropped, causing a double free.